[unreadable] This proposal tests the generalization of a standardized client-treatment matching interview and decision-tree algorithm (the Client Matching Protocol, or CMP) through an 18-month secondary analysis of the Drug Abuse Treatment Outcome Study (DATOS) database. The investigative team's previous study of Therapeutic Community (TC)-oriented agencies found that clients entering outpatient and residential treatment settings in which there was a concordance with the CMP algorithm (matched clients) showed significantly higher rates of treatment completion and long-term retention than clients entering settings that were discordant with the CMP algorithm (mismatched clients). The present study uses the DATOS variables to recreate the CMP algorithm. The study extends the previous research by 1) testing the generalization of the CMP to non-TC residential and outpatient programs, 2) determining the effect of matching on treatment process, and 3) testing the generalization of the matching effect to one- and five-year treatment outcomes. Additional research questions explore the extension of the CMP algorithm to short-term residential and methadone outpatient treatment, and to the interaction between the CMP match and organizational and client variables. Non-parametric statistics, ANOVA, logistic and multiple regression, and Structural Equation Modeling test the effects of matching and the interaction of matching and the program and client characteristics. The present study contains important research and clinical implications. This 18-month study contains significant implications for both treatment and research in that it will provide empirical clarification of whether and how matching contributes to treatment improvement. Specifically replicating a matching effect in the DATOS modalities will establish the empirical basis for a controlled study of matching and a refined version of the matching protocol for use in clinical practice. [unreadable] [unreadable]